I have a copy of a 1969 Chevelle SS396 window sticker, built at Leeds (Kansas City, Missouri). It shows the F40 Special "Front and Rear Suspension" as an $5.30 option and not part of the SS package.
A option package description I have indicates the F40 suspension option was just springs.
Here's what it says in my literture
Suspension, Special Front and Rear: Includes special front and 2700lb capacity rear springs...................F40
Listed as HD suspension in assembly manual.
[This message has been edited by elcamino (edited 02-09-2002).]